I'm sure that 5 of us could sit down and hatch plausible theories as to why you'd see this trend moving up. But in recent years, there was some anecdotal belief that many women were "holding out" for men who met a very discriminating set of minimums (salary, education, etc.), with influencers everywhere telling them not to "settle for less" than they should feel entitled to. And if there were truth to that, it would lend itself to the trend of single women in their late 30's and 40's who had never married nor been able to start a family.
I suppose it's possible that this trend could finally be a reversal of that phenomenon, with many women maybe simply marrying for compatibility beyond the Vogue Magazine checklist of must-haves. That would probably be a good thing for society.